Air cleaners and purifiers are widely used for removing foreign substances from air. The foreign substances can include pollen, dander, smoke, pollutants, dust, etc. In addition, an air cleaner can be used to circulate room air. An air cleaner can be used in many settings, including at home, in offices, etc.
One type of air cleaner is an electrostatic precipitator. An electrostatic precipitator operates by creating an electrical field. Dirt and debris in the air becomes ionized when it is brought into the electrical field by an airflow. Charged positive and negative electrodes in the electrostatic precipitator air cleaner, such as positive and negative plates, attract the ionized dirt and debris. The electrodes can release the dirt and debris when not powered, allowing the accumulated dirt and debris to drop into a catch basin. In addition, the electrostatic precipitator can typically be removed and cleaned. Because the electrostatic precipitator comprises electrodes or plates through which airflow can easily and quickly pass, only a low amount of energy is required to generate the airflow. As a result, foreign objects in the air can be efficiently and effectively removed without the need for a mechanical filter element.
One type of electrostatic precipitator includes an electrostatic air moving mechanism that creates electrical field pulses in order to charge (i.e., ionize) the air. The device alternatingly charges and repulses the surrounding air in order to create air movement. However, although the resulting airflow is quiet, it is also very weak, and such air cleaner systems take a very long time to cycle through an average room air volume. In addition, an electrostatic air movement does not allow much control over the airflow volume, and is an on or off type of air movement system.
Another type of electrostatic precipitator is offered for sale by Brookstone, Inc., Nashua, N.H. The Brookstone air cleaner includes a single fan that draws air in at the base, ducts the airflow to the top of the tower, and draws the airflow down through an elongate electrostatic precipitator. The Brookstone electrostatic precipitator is tall and narrow, and the downward airflow travels the height of the electrostatic precipitator. The airflow is ultimately exhausted at a port in the base.
This prior art device has several drawbacks. The long, serpentine airflow path results in airflow energy loss due to its length and its corners. In addition, the long, looping airflow path can cause increased noise of operation. Moreover, the airflow is constrained to travel the full height of the electrostatic precipitator, reducing the contact of the electrostatic precipitator with the airflow and impairing the efficiency of the prior art device.